[SOLVED] USB Recording Bleed on HX Stomp

[rajas-PL]

Hey folks,

Just wanted to share something we ran into that might save someone some serious head-scratching.

 

We were recording bass using HX Stomp as a USB interface — sending both dry and wet signals to the DAW. Everything sounded fine in the mix, but when we soloed the bass track (especially during quiet parts where the bass wasn’t playing), we heard a faint but very real bleed from other tracks, mainly the DAW’s metronome click (that annoying high-pitched beep type).

 

At first we thought it was some weird routing issue in the DAW or maybe a ground loop. Spent almost 2 hours with our guitarist going through all possible causes.

 

Turns out… the problem was physical.

If you have anything plugged into the analog L/R outputs of the HX Stomp — even if you’re not using them — you get USB bleed on the recorded tracks. The dry and wet USB channels both picked it up.

 

The fix?

Just unplug the 1/4” L/R main outs while recording via USB, and use the headphone out for monitoring. As soon as we left the analog outs empty, the bleed disappeared completely from the USB recordings.

 

Hope this helps someone out there. We were going nuts trying to track it down.

[datacommando]

On 6/29/2025 at 8:30 PM, rajas-PL said:

 

Turns out… the problem was physical.

If you have anything plugged into the analog L/R outputs of the HX Stomp — even if you’re not using them — you get USB bleed on the recorded tracks. The dry and wet USB channels both picked it up.

 

The fix?

Just unplug the 1/4” L/R main outs while recording via USB, and use the headphone out for monitoring. As soon as we left the analog outs empty, the bleed disappeared completely from the USB recordings.

 

Hi,

 

I think you might have not read the HX Stomp 3.8 Owner’s Manual - Page 61 - USB Audio. I suggest that you do.

 

https://line6.com/data/6/0a00051afdda673cccdb61c9c/application/pdf/HX Stomp 3.80 Owner's Manual - English .pdf

 

When you connect the Stomp to a DAW via USB, all processed sound from your guitar/bass on path A is sent over USB 1&2, or if using Path B, then that processed audio is sent on channels 3&4. If you have a track set to record input from USB 5&6, you will capture the DI (dry) signal which can be used to re-amp you track.

 

Now, regarding playback of you recorded audio - if your DAW Main Stereo Out is set to USB 1&2, all audio tracks will be sent back to the HX Stomp on USB channels 1&2. At this point, the idea is that you would have your studio monitors connected to the main L/R Outs in order to be able to hear your mix playback through the Stomp without any further processing added. This is normal. (You didn’t mention what was attached to the L/R Outs, when you experienced what you describe as “bleed”). Likewise, any tracks set to playback over USB 3&4 will be sent back through the HX Stomp to be output from the SEND (stereo) jack socket as a second monitor option. Furthermore, if you need to re-amp your dry track, that should be set to output from your DAW on USB 5&6 (note: the HX Stomp input needs to be set on 5&6) then you can use a completely different preset to send the dry signal back into the DAW to be re-recorded on a fresh track armed to receive USB1&2.

I have been using my Helix floor unit, almost daily for the past 10 years, to record into Logic Pro X on my Mac, and have never encountered a situation such as the one you describe.

Hope this helps/makes sense.

[Schmalle]

I suspect the cause is a dual-ground problem:

 

The device connected to the USB port has a different potential than the one connected to the output. The signal at the output shifts the ground difference slightly, causing the HX Stomp ground to follow the output signal. Since the input is also connected to this ground, it senses the output signal. Thus, the output signal bleeds through the ground to the input signal.

 

If I'm right, the strength of the bleeding signal can be adjusted with the VOLUME control as well as the instrument's volume knob. Connecting the Outs or USB to a properly grounded device should also fix this.

[theElevators]

BTW also if you are recording with studio monitors, the sound from the monitors gets picked up by the guitar/bass pickups as well!  I was listening to isolated tracks from one of my concerts and could faintly hear the rest of the band in the isolated track!  I was running my guitar direct btw... But it's a live concert, so that was more pronounced, with all the distortion, all pickups are more-ore-less microphonic.  

[rajas-PL]

On 6/30/2025 at 3:08 PM, Schmalle said:

I suspect the cause is a dual-ground problem:

 

The device connected to the USB port has a different potential than the one connected to the output. The signal at the output shifts the ground difference slightly, causing the HX Stomp ground to follow the output signal. Since the input is also connected to this ground, it senses the output signal. Thus, the output signal bleeds through the ground to the input signal.

 

If I'm right, the strength of the bleeding signal can be adjusted with the VOLUME control as well as the instrument's volume knob. Connecting the Outs or USB to a properly grounded device should also fix this.

 

Yes, that actually sounds very likely.

 

We’ve tested it in multiple ways – with different monitor levels, even with the monitors completely off... The last test was with the guitar fully disconnected (so zero chance of the pickups catching anything – unless we start assuming cables can pick up sound on their own).

 

On top of that, my guitarist is running almost the exact same setup with a Stomp XL and we’ve never had any issues there.

My bass rig is pretty minimal: an HX Stomp, a MIDI controller, and an expression pedal working via MIDI… the only difference is that my Stomp’s outputs are wired inside the pedalboard to one of those Rockboard patch modules. When I unplug the HX Stomp from that patchbay, the problem disappears instantly, so it really does point to a physical issue.

 

The bleed is so minimal that if it weren’t for the click sound, you probably wouldn’t even notice it. So yes, it seems to be exactly the kind of physical ground issue you’re describing.

 

Another thought – could it be that the Stomp’s outputs aren’t actually combo XLR outs but stereo TRS jacks? Maybe when I plug in mono jacks for L and R (which is totally fine per the manual) it’s causing some kind of coupling? I’m running the bass in stereo because I split the signal into low and high frequencies.

 

BTW... these units are seriously powerful though – I once told my guitarist during rehearsal, “Plug your guitar in, I’ll dial in a quick preset for you…” and after I dropped an ENGL block on his tone, he ordered a Helix two weeks later.